Macroscopic and microscopic picture of negative capacitance operation in ferroelectric capacitors

The negative capacitance (NC) operation of ferroelectric materials has been originally proposed based on a homogeneous Landau theory, leading to a simple NC stabilization condition expressed in terms of macroscopic...

Improved Approach to Robust Control for Type-2 T-S Fuzzy Systems

This paper is concerned with the robust stability conditions to stabilize the type 2 Takagi-Sugeno (T-S) fuzzy systems. The conditions effectively handle parameter uncertainties using lower and upper membership functions. To improve the solvability of the stability conditions, we establish a multigain controller with comprehensive information of the lower and upper membership grades. In addition, a well-organized relaxation technique is proposed to fully exploit relationship among fuzzy weighting functions and their lower and upper membership grades, which enlarges a set of feasible solutions. Therefore, we derive a less conservative stabilization condition in terms of linear matrix inequalities (LMIs) than those in the literature. Two simulation examples illustrate the effectiveness and robustness of the derived stabilization conditions.

Effect of Stabilization Conditions on the Fabrication of Carbon Membranes for CO2 Separation

Preparation of carbon membranes has rapidly attracted much attention in gas separation processes because of thermal and chemical stabilities and exhibit superior separation performance. Carbon hollow fiber membranes (CHFM)s derived from polymer blend of polyetherimide (PEI) and polyvinylpyrrolidone (PVP) were extensively prepared through stabilization under air atmosphere followed by carbonization under N2 atmosphere. The effects of the stabilization temperature on the morphological structure and gas permeation properties were investigated by means of scanning electron microscopy (SEM) and single gas permeation system. Experimental results indicate that the transport mechanism of small gas molecules of N2, CO2, and CH4 is dominated by the molecular sieving effect. Based on morphological structure and gas permeation properties, an optimum stabilization condition for the preparation of CHFM derived from PEI/PVP was found at 300°C under air atmosphere. The selectivity of about 55 and 41 for CO2/CH4 and CO2/N2, respectively, were obtained.

Mass of the Stabilized Radion in the Limit of Finite Quartic Coupling

We present an exact treatment of the modulus stabilization condition with the general boundary conditions of the bulk scalar field in the Randall-Sundrum model. We find analytical expressions for the value of the modulus and the mass of the radion.